Journal of Korean Neurosurgical Society

  • 제64권5호
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  • Pages.677-692
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  • 2021
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  • 2005-3711(pISSN)
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  • 1598-7876(eISSN)
대한신경외과학회 (The Korean Neurosurgical Society)
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Preoperative Radiological Parameters to Predict Clinical and Radiological Outcomes after Laminoplasty

  • Lee, Su Hun (Department of Neurosurgery, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital) ;
  • Son, Dong Wuk (Department of Neurosurgery, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital) ;
  • Shin, Jun Jae (Department of Neurosurgery, Yongin Severance Hospital, Yonsei University College of Medicine) ;
  • Ha, Yoon (Department of Neurosurgery, Spine and Spinal Cord Institute, Severance Hospital, Yonsei University College of Medicine) ;
  • Song, Geun Sung (Department of Neurosurgery, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital) ;
  • Lee, Jun Seok (Department of Neurosurgery, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital) ;
  • Lee, Sang Weon (Department of Neurosurgery, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital)
  • 투고 : 2020.10.14
  • 심사 : 2020.12.19
  • 발행 : 2021.09.01
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초록

Many studies have focused on pre-operative sagittal alignment parameters which could predict poor clinical or radiological outcomes after laminoplasty. However, the influx of too many new factors causes confusion. This study reviewed sagittal alignment parameters, predictive of clinical or radiological outcomes, in the literature. Preoperative kyphotic alignment was initially proposed as a predictor of clinical outcomes. The clinical significance of the K-line and K-line variants also has been studied. Sagittal vertical axis, T1 slope (T1s), T1s-cervical lordosis (CL), anterolisthesis, local kyphosis, the longitudinal distance index, and range of motion were proposed to have relationships with clinical outcomes. The relationship between loss of cervical lordosis (LCL) and T1s has been widely studied, but controversy remains. Extension function, the ratio of CL to T1s (CL/T1s), and Sharma classification were recently proposed as LCL predictors. In predicting postoperative kyphosis, T1s cannot predict postoperative kyphosis, but a low CL/T1s ratio was associated with postoperative kyphosis.

키워드

과제정보

This study was supported by Research institute for Convergence of biomedical science and technology (30-2018-020), Pusan National University Yangsan Hospital.

참고문헌

  1. Aita I, Wadano Y, Yabuki T : Curvature and range of motion of the cervical spine after laminaplasty. J Bone Joint Surg Am 82 : 1743-1748, 2000 https://doi.org/10.2106/00004623-200012000-00008
  2. Baba H, Uchida K, Maezawa Y, Furusawa N, Azuchi M, Imura S : Lordotic alignment and posterior migration of the spinal cord following en bloc open-door laminoplasty for cervical myelopathy: a magnetic resonance imaging study. J Neurol 243 : 626-632, 1996 https://doi.org/10.1007/BF00878657
  3. Bajamal AH, Kim SH, Arifianto MR, Faris M, Subagio EA, Roitberg B, et al. : Posterior surgical techniques for cervical spondylotic myelopathy: WFNS Spine Committee recommendations. Neurospine 16 : 421-434, 2019 https://doi.org/10.14245/ns.1938274.137
  4. Batzdorf U, Batzdorff A : Analysis of cervical spine curvature in patients with cervical spondylosis. Neurosurgery 22 : 827-836, 1988 https://doi.org/10.1227/00006123-198805000-00004
  5. Batzdorf U, Flannigan BD : Surgical decompressive procedures for cervical spondylotic myelopathy. A study using magnetic resonance imaging. Spine (Phila Pa 1976) 16 : 123-127, 1991 https://doi.org/10.1097/00007632-199116020-00004
  6. Cao J, Zhang J, Yang D, Yang L, Shen Y : Multivariate analysis of factors associated with kyphotic deformity after laminoplasty in cervical spondylotic myelopathy patients without preoperative kyphotic alignment. Sci Rep 7 : 43443, 2017 https://doi.org/10.1038/srep43443
  7. Chen HY, Yang MH, Lin YP, Lin FH, Chen PQ, Hu MH, et al. : Impact of cervical sagittal parameters and spinal cord morphology in cervical spondylotic myelopathy status post spinous process-splitting laminoplasty. Eur Spine J 29 : 1052-1060, 2020 https://doi.org/10.1007/s00586-019-06247-z
  8. Chiba K, Toyama Y, Watanabe M, Maruiwa H, Matsumoto M, Hirabayashi K : Impact of longitudinal distance of the cervical spine on the results of expansive open-door laminoplasty. Spine (Phila Pa 1976) 25 : 2893-2898, 2000 https://doi.org/10.1097/00007632-200011150-00010
  9. Chiba K, Ogawa Y, Ishii K, Takaishi H, Nakamura M, Maruiwa H, et al. : Long-term results of expansive open-door laminoplasty for cervical myelopathy--average 14-year follow-up study. Spine (Phila Pa 1976) 31 : 2998-3005, 2006 https://doi.org/10.1097/01.brs.0000250307.78987.6b
  10. Cho JH, Ha JK, Kim DG, Song KY, Kim YT, Hwang CJ, et al. : Does preoperative T1 slope affect radiological and functional outcomes after cervical laminoplasty? Spine (Phila Pa 1976) 39 : E1575-E1581, 2014 https://doi.org/10.1097/BRS.0000000000000614
  11. Deora H, Kim SH, Behari S, Rudrappa S, Rajshekhar V, Zileli M, et al. : Anterior surgical techniques for cervical spondylotic myelopathy: WFNS Spine Committee recommendations. Neurospine 16 : 408-420, 2019 https://doi.org/10.14245/ns.1938250.125
  12. Fujiwara H, Oda T, Makino T, Moriguchi Y, Yonenobu K, Kaito T : Impact of cervical sagittal alignment on axial neck pain and health-related quality of life after cervical laminoplasty in patients with cervical spondylotic myelopathy or ossification of the posterior longitudinal ligament: a prospective comparative study. Clin Spine Surg 31 : E245-E251, 2018 https://doi.org/10.1097/BSD.0000000000000619
  13. Fujiyoshi T, Yamazaki M, Kawabe J, Endo T, Furuya T, Koda M, et al. : A new concept for making decisions regarding the surgical approach for cervical ossification of the posterior longitudinal ligament: the K-line. Spine (Phila Pa 1976) 33 : E990-E993, 2008 https://doi.org/10.1097/BRS.0b013e318188b300
  14. Head J, Rymarczuk G, Stricsek G, Velagapudi L, Maulucci C, Hoelscher C, et al. : Ossification of the posterior longitudinal ligament: surgical approaches and associated complications. Neurospine 16 : 517-529, 2019 https://doi.org/10.14245/ns.1938222.111
  15. Hirabayashi K, Miyakawa J, Satomi K, Maruyama T, Wakano K : Operative results and postoperative progression of ossification among patients with ossification of cervical posterior longitudinal ligament. Spine (Phila Pa 1976) 6 : 354-364, 1981 https://doi.org/10.1097/00007632-198107000-00005
  16. Hirabayashi K, Watanabe K : A review of my invention of expansive laminoplasty. Neurospine 16 : 379-382, 2019 https://doi.org/10.14245/ns.1938272.136
  17. Ijima Y, Furuya T, Ota M, Maki S, Saito J, Kitamura M, et al. : The K-line in the cervical ossification of the posterior longitudinal ligament is different on plain radiographs and CT images. J Spine Surg 4 : 403-407, 2018 https://doi.org/10.21037/jss.2018.05.23
  18. Ishibashi K : Expansive laminoplasty by sagittal splitting of the spinous process for cervical myelopathy: correlation of clinical results with morphological changes in the cervical spine. Kurume Med J 47 : 135-145, 2000 https://doi.org/10.2739/kurumemedj.47.135
  19. Ito K, Yukawa Y, Ito K, Machino M, Kanbara S, Nakashima H, et al. : Dynamic changes in the spinal cord cross-sectional area in patients with myelopathy due to cervical ossification of posterior longitudinal ligament. Spine J 15 : 461-466, 2015 https://doi.org/10.1016/j.spinee.2014.10.001
  20. Itoki K, Kurokawa R, Shingo T, Kim P : Effect of myoarchitectonic spinolaminoplasty on concurrent hypertension in patients with cervical spondylotic myelopathy. Neurospine 15 : 77-85, 2018 https://doi.org/10.14245/ns.1836020.010
  21. Iwasaki M, Kawaguchi Y, Kimura T, Yonenobu K : Long-term results of expansive laminoplasty for ossification of the posterior longitudinal ligament of the cervical spine: more than 10 years follow up. J Neurosurg 96(2 Suppl) : 180-189, 2002
  22. Joshi RS, Haddad AF, Lau D, Ames CP : Artificial intelligence for adult spinal deformity. Neurospine 16 : 686-694, 2019 https://doi.org/10.14245/ns.1938414.207
  23. Kato M, Namikawa T, Matsumura A, Konishi S, Nakamura H : Effect of cervical sagittal balance on laminoplasty in patients with cervical myelopathy. Global Spine J 7 : 154-161, 2017 https://doi.org/10.1177/2192568217694011
  24. Kawakami M, Tamaki T, Ando M, Yamada H, Yoshida M : Relationships between sagittal alignment of the cervical spine and morphology of the spinal cord and clinical outcomes in patients with cervical spondylotic myelopathy treated with expansive laminoplasty. J Spinal Disord Tech 15 : 391-397, 2002 https://doi.org/10.1097/00024720-200210000-00008
  25. Kawanabe Y, Fujimoto M, Sato T : Cervical open-door laminoplasty by hydroxyapatite implant insertion without suturing. Neurospine 15 : 362-367, 2018 https://doi.org/10.14245/ns.1836106.053
  26. Khan O, Badhiwala JH, Wilson JRF, Jiang F, Martin AR, Fehlings MG : Predictive modeling of outcomes after traumatic and nontraumatic spinal cord injury using machine learning: review of current progress and future directions. Neurospine 16 : 678-685, 2019 https://doi.org/10.14245/ns.1938390.195
  27. Kim B, Yoon DH, Ha Y, Yi S, Shin DA, Lee CK, et al. : Relationship between T1 slope and loss of lordosis after laminoplasty in patients with cervical ossification of the posterior longitudinal ligament. Spine J 16 : 219-225, 2016 https://doi.org/10.1016/j.spinee.2015.10.042
  28. Kim DH, Lee CH, Ko YS, Yang SH, Kim CH, Park SB, et al. : The clinical implications and complications of anterior versus posterior surgery for multilevel cervical ossification of the posterior longitudinal ligament; an updated systematic review and meta-analysis. Neurospine 16 : 530-541, 2019 https://doi.org/10.14245/ns.1938326.163
  29. Kim M, Yun J, Cho Y, Shin K, Jang R, Bae HJ, et al. : Deep learning in medical imaging. Neurospine 16 : 657-668, 2019 https://doi.org/10.14245/ns.1938396.198
  30. Kim SW, Hai DM, Sundaram S, Kim YC, Park MS, Paik SH, et al. : Is cervical lordosis relevant in laminoplasty? Spine J 13 : 914-921, 2013 https://doi.org/10.1016/j.spinee.2013.02.032
  31. Kim TH, Lee SY, Kim YC, Park MS, Kim SW : T1 slope as a predictor of kyphotic alignment change after laminoplasty in patients with cervical myelopathy. Spine (Phila Pa 1976) 38 : E992-E997, 2013 https://doi.org/10.1097/BRS.0b013e3182972e1b
  32. Kwon SY, Shin JJ, Lee JH, Cho WH : Prognostic factors for surgical outcome in spinal cord injury associated with ossification of the posterior longitudinal ligament (OPLL). J Orthop Surg Res 10 : 94, 2015 https://doi.org/10.1186/s13018-015-0235-3
  33. Lee BJ, Park JH, Jeon SR, Rhim SC, Roh SW : Importance of the preoperative cross-sectional area of the semispinalis cervicis as a risk factor for loss of lordosis after laminoplasty in patients with cervical spondylotic myelopathy. Eur Spine J 27 : 2720-2728, 2018 https://doi.org/10.1007/s00586-018-5726-6
  34. Lee CK, Shin DA, Yi S, Kim KN, Shin HC, Yoon DH, et al. : Correlation between cervical spine sagittal alignment and clinical outcome after cervical laminoplasty for ossification of the posterior longitudinal ligament. J Neurosurg Spine 24 : 100-107, 2016 https://doi.org/10.3171/2015.4.SPINE141004
  35. Lee DH, Kim H, Lee HS, Noh H, Kim NH, Hwang C, et al. : The Kappa line - a predictor of neurologic outcome after cervical laminoplasty. ISASS13 Oral Podium and Oral Poster Presentation; 2013 Apr 3-5; Vancouver, Canada. Rosemont (IL) : ISASS; 2013
  36. Lee JS, Son DW, Lee SH, Kim DH, Lee SW, Song GS : The predictable factors of the postoperative kyphotic change of sagittal alignment of the cervical spine after the laminoplasty. J Korean Neurosurg Soc 60 : 577-583, 2017 https://doi.org/10.3340/jkns.2017.0505.007
  37. Lee SH, Kim KT, Lee JH, Kang KC : Presentation #32: posterior cervical spinal cord shift following posterior decompression and prediction of persistent anterior spinal cord compression using K-plane: a three dimensional modification of K-line on MRI. Spine Journal Meeting Abstracts 2016 : 155-157, 2016
  38. Lee SH, Son DW, Lee JS, Kim DH, Sung SK, Lee SW, et al. : Differences in cervical sagittal alignment changes in patients undergoing laminoplasty and anterior cervical discectomy and fusion. Neurospine 15 : 91-100, 2018 https://doi.org/10.14245/ns.1834864.432
  39. Lee SH, Son DW, Lee JS, Sung SK, Lee SW, Song GS : Does extension dysfunction affect postoperative loss of cervical lordosis in patients who undergo laminoplasty? Spine (Phila Pa 1976) 44 : E456-E464, 2019 https://doi.org/10.1097/BRS.0000000000002887
  40. Li J, Zhang Y, Zhang N, Xv ZK, Li H, Chen G, et al. : Clinical outcome of laminoplasty for cervical ossification of the posterior longitudinal ligament with K-line (-) in the neck neutral position but K-line (+) in the neck extension position: a retrospective observational study. Medicine (Baltimore) 96 : e6964, 2017 https://doi.org/10.1097/MD.0000000000006964
  41. Li XY, Kong C, Sun XY, Guo MC, Ding JZ, Yang YM, et al. : Influence of the ratio of C2-C7 Cobb angle to T1 slope on cervical alignment after laminoplasty. World Neurosurg 124 : e659-e666, 2019 https://doi.org/10.1016/j.wneu.2018.12.181
  42. Lin BJ, Hong KT, Lin C, Chung TT, Tang CT, Hueng DY, et al. : Impact of global spine balance and cervical regional alignment on determination of postoperative cervical alignment after laminoplasty. Medicine (Baltimore) 97 : e13111, 2018 https://doi.org/10.1097/MD.0000000000013111
  43. Maruo K, Moriyama T, Tachibana T, Inoue S, Arizumi F, Daimon T, et al. : The impact of dynamic factors on surgical outcomes after double-door laminoplasty for ossification of the posterior longitudinal ligament of the cervical spine. J Neurosurg Spine 21 : 938-943, 2014 https://doi.org/10.3171/2014.8.SPINE131197
  44. Masaki Y, Yamazaki M, Okawa A, Aramomi M, Hashimoto M, Koda M, et al. : An analysis of factors causing poor surgical outcome in patients with cervical myelopathy due to ossification of the posterior longitudinal ligament: anterior decompression with spinal fusion versus laminoplasty. J Spinal Disord Tech 20 : 7-13, 2007 https://doi.org/10.1097/01.bsd.0000211260.28497.35
  45. Matsuoka Y, Suzuki H, Endo K, Sawaji Y, Murata K, Nishimura H, et al. : Small sagittal vertical axis accompanied with lumbar hyperlordosis as a risk factor for developing postoperative cervical kyphosis after expansive open-door laminoplasty. J Neurosurg Spine 29 : 176-181, 2018 https://doi.org/10.3171/2017.12.SPINE17557
  46. Matsuyama Y, Kawakami N, Yanase M, Yoshihara H, Ishiguro N, Kameyama T, et al. : Cervical myelopathy due to OPLL: clinical evaluation by MRI and intraoperative spinal sonography. J Spinal Disord Tech 17 : 401-404, 2004 https://doi.org/10.1097/01.bsd.0000112087.85112.86
  47. Miyazaki M, Ishihara T, Notani N, Kanezaki S, Tsumura H : Relationship of T1 slope with loss of lordosis and surgical outcomes after laminoplasty for cervical ossification of the posterior longitudinal ligament. Clin Neurol Neurosurg 164 : 19-24, 2018 https://doi.org/10.1016/j.clineuro.2017.11.007
  48. Ogawa Y, Toyama Y, Chiba K, Matsumoto M, Nakamura M, Takaishi H, et al. : Long-term results of expansive open-door laminoplasty for ossification of the posterior longitudinal ligament of the cervical spine. J Neurosurg Spine 1 : 168-174, 2004 https://doi.org/10.3171/spi.2004.1.2.0168
  49. Oh JK, Hong JT, Kang DH, Kim SW, Kim SW, Kim YJ, et al. : Epidemiology of C5 palsy after cervical spine surgery: a 21-center study. Neurospine 16 : 558-562, 2019 https://doi.org/10.14245/ns.1938142.071
  50. Oichi T, Oshima Y, Taniguchi Y, Matsubayashi Y, Chikuda H, Takeshita K, et al. : Cervical anterolisthesis: a predictor of poor neurological outcomes in cervical spondylotic myelopathy patients after cervical laminoplasty. Spine (Phila Pa 1976) 41 : E467-E473, 2016 https://doi.org/10.1097/BRS.0000000000001277
  51. Oshima Y, Takeshita K, Taniguchi Y, Matsubayashi Y, Doi T, Ohya J, et al. : Effect of preoperative sagittal balance on cervical laminoplasty outcomes. Spine (Phila Pa 1976) 41 : E1265-E1270, 2016 https://doi.org/10.1097/BRS.0000000000001615
  52. Papavero L, Schmeiser G, Kothe R, Boszczyk B, Heese O, Kawaguchi Y, et al. : Degenerative cervical myelopathy: a 7-letter coding system that supports decision-making for the surgical approach. Neurospine 17 : 164-171, 2020 https://doi.org/10.14245/ns.1938010.005
  53. Parthiban J, Alves OL, Chandrachari KP, Ramani P, Zileli M : Value of surgery and nonsurgical approaches for cervical spondylotic myelopathy: WFNS Spine Committee recommendations. Neurospine 16 : 403-407, 2019 https://doi.org/10.14245/ns.1938238.119
  54. Rao H, Huang Y, Lan Z, Xu Z, Li G, Xu W : Does preoperative T1 slope and cervical lordosis mismatching affect surgical outcomes after laminoplasty in patients with cervical spondylotic myelopathy? World Neurosurg 130 : e687-e693, 2019 https://doi.org/10.1016/j.wneu.2019.06.193
  55. Sakai K, Yoshii T, Hirai T, Arai Y, Matsukura Y, Okawa A : The K-line tilt, a novel radiographic parameter of cervical sagittal balance, is a predictor of postoperative kyphotic deformity after laminoplasty for cervical myelopathy caused by ossification of the posterior longitudinal ligament. Proceedings of the 44th Annual Meeting of the Cervical Spine Research Society; 2016 Dec 1-3; Toronto, Canada. Brookfield (WI) : Milwaukee; 2017
  56. Sakai K, Yoshii T, Hirai T, Arai Y, Torigoe I, Tomori M, et al. : Cervical sagittal imbalance is a predictor of kyphotic deformity after laminoplasty in cervical spondylotic myelopathy patients without preoperative kyphotic alignment. Spine (Phila Pa 1976) 41 : 299-305, 2016 https://doi.org/10.1097/BRS.0000000000001206
  57. Sakaura H, Ohnishi A, Yamagishi A, Ohwada T : Differences in postoperative changes of cervical sagittal alignment and balance after laminoplasty between cervical spondylotic myelopathy and cervical ossification of the posterior longitudinal ligament. Global Spine J 9 : 266-271, 2019 https://doi.org/10.1177/2192568218784951
  58. Satomi K, Nishu Y, Kohno T, Hirabayashi K : Long-term follow-up studies of open-door expansive laminoplasty for cervical stenotic myelopathy. Spine (Phila Pa 1976) 19 : 507-510, 1994 https://doi.org/10.1097/00007632-199403000-00003
  59. Schwartz JT, Gao M, Geng EA, Mody KS, Mikhail CM, Cho SK : Applications of machine learning using electronic medical records in spine surgery. Neurospine 16 : 643-653, 2019 https://doi.org/10.14245/ns.1938386.193
  60. Seichi A, Takeshita K, Ohishi I, Kawaguchi H, Akune T, Anamizu Y, et al. : Long-term results of double-door laminoplasty for cervical stenotic myelopathy. Spine (Phila Pa 1976) 26 : 479-487, 2001 https://doi.org/10.1097/00007632-200103010-00010
  61. Sharma R, Borkar SA, Goda R, Kale SS : Which factors predict the loss of cervical lordosis following cervical laminoplasty? A review of various indices and their clinical implications. Surg Neurol Int 10 : 147, 2019 https://doi.org/10.25259/SNI_339_2019
  62. Sharma R, Borkar S, Katiyar V, Goda R, Phalak M, Joseph L, et al. : Interplay of dynamic extension reserve and T1 slope in determining the loss of cervical lordosis following laminoplasty: a novel classification system. World Neurosurg 136 : e33-e40, 2020 https://doi.org/10.1016/j.wneu.2019.08.212
  63. Shimokawa N, Sato H, Matsumoto H, Takami T : Review of radiological parameters, imaging characteristics, and their effect on optimal treatment approaches and surgical outcomes for cervical ossification of the posterior longitudinal ligament. Neurospine 16 : 506-516, 2019 https://doi.org/10.14245/ns.1938268.134
  64. Suda K, Abumi K, Ito M, Shono Y, Kaneda K, Fujiya M : Local kyphosis reduces surgical outcomes of expansive open-door laminoplasty for cervical spondylotic myelopathy. Spine (Phila Pa 1976) 28 : 1258-1262, 2003 https://doi.org/10.1097/01.BRS.0000065487.82469.D9
  65. Suk KS, Kim KT, Lee JH, Lee SH, Lim YJ, Kim JS : Sagittal alignment of the cervical spine after the laminoplasty. Spine (Phila Pa 1976) 32 : E656-E660, 2007 https://doi.org/10.1097/BRS.0b013e318158c573
  66. Sun LQ, Li M, Li YM : Prediction of incomplete decompression after cervical laminoplasty on magnetic resonance imaging: the modified K-line. Clin Neurol Neurosurg 146 : 12-17, 2016 https://doi.org/10.1016/j.clineuro.2016.04.013
  67. Tamai K, Suzuki A, Yabu A, Terai H, Hoshino M, Toyoda H, et al. : Clinical impact of cervical imbalance on surgical outcomes of laminoplasty: a propensity score-matching analysis. Clin Spine Surg 33 : E1-E7, 2020 https://doi.org/10.1097/BSD.0000000000000849
  68. Taniyama T, Hirai T, Yamada T, Yuasa M, Enomoto M, Yoshii T, et al. : Modified K-line in magnetic resonance imaging predicts insufficient decompression of cervical laminoplasty. Spine (Phila Pa 1976) 38 : 496-501, 2013 https://doi.org/10.1097/BRS.0b013e318273a4f7
  69. Taniyama T, Hirai T, Yoshii T, Yamada T, Yasuda H, Saito M, et al. : Modified K-line in magnetic resonance imaging predicts clinical outcome in patients with nonlordotic alignment after laminoplasty for cervical spondylotic myelopathy. Spine (Phila Pa 1976) 39 : E1261-E1268, 2014 https://doi.org/10.1097/BRS.0000000000000531
  70. Vaziri S, Lockney DT, Dru AB, Polifka AJ, Fox WC, Hoh DJ : Does ossification of the posterior longitudinal ligament progress after fusion? Neurospine 16 : 483-491, 2019 https://doi.org/10.14245/ns.1938286.143
  71. Wilson JRF, Badhiwala JH, Moghaddamjou A, Martin AR, Fehlings MG : Degenerative cervical myelopathy; a review of the latest advances and future directions in management. Neurospine 16 : 494-505, 2019 https://doi.org/10.14245/ns.1938314.157
  72. Yamazaki A, Homma T, Uchiyama S, Katsumi Y, Okumura H : Morphologic limitations of posterior decompression by midsagittal splitting method for myelopathy caused by ossification of the posterior longitudinal ligament in the cervical spine. Spine (Phila Pa 1976) 24 : 32-34, 1999 https://doi.org/10.1097/00007632-199901010-00008
  73. Yonenobu K, Abumi K, Nagata K, Taketomi E, Ueyama K : Interobserver and intraobserver reliability of the japanese orthopaedic association scoring system for evaluation of cervical compression myelopathy. Spine (Phila Pa 1976) 26 : 1890-1894; discussion 1895, 2001 https://doi.org/10.1097/00007632-200109010-00014
  74. Zhang JT, Li JQ, Niu RJ, Liu Z, Tong T, Shen Y : Predictors of cervical lordosis loss after laminoplasty in patients with cervical spondylotic myelopathy. Eur Spine J 26 : 1205-1210, 2017 https://doi.org/10.1007/s00586-017-4971-4
  75. Zileli M : Recommendations of WFNS Spine Committee. Neurospine 16 : 383-385, 2019 https://doi.org/10.14245/ns.19int003
  76. Zileli M, Borkar SA, Sinha S, Reinas R, Alves OL, Kim SH, et al. : Cervical spondylotic myelopathy: natural course and the value of diagnostic techniques -WFNS Spine Committee recommendations. Neurospine 16 : 386-402, 2019 https://doi.org/10.14245/ns.1938240.120
  77. Zileli M, Maheshwari S, Kale SS, Garg K, Menon SK, Parthiban J : Outcome measures and variables affecting prognosis of cervical spondylotic myelopathy: WFNS Spine Committee recommendations. Neurospine 16 : 435-447, 2019 https://doi.org/10.14245/ns.1938196.098